The present invention relates to GTAW (gas tungsten arc welding) and TIG (tungsten inert gas) welding torches, and more particularly, to an improved method of construction that fixes the handle to the torch body in a more advantageous manner. Traditionally, the welding torch body was constructed using a rigid plastic insulation material such as phenolic or nylon. The rigid plastic insulation connected to the handle via a threaded connection that was also made from a plastic material. The plastic insulation was subject to physical limitations including melting, cracking, chipping, and in some cases, electrical breakdown.
More recently, welding torch bodies have been comprised of rubber insulation, usually silicone rubber, which has high heat resistance. The rubber insulation resists cracking and chipping, and has excellent insulation properties. The rubber insulation also allows the welder, as the operator of the welding torch, to bend or form the torch body to a more comfortable working position. The torch body is more effectively insulated with rubber than with plastic because the rubber insulation is less electrically conductive than a similar plastic insulation component.
The handle connection of a rubber insulated torch body is a friction-type connection. The rubber torch body is molded with a series of rings, or xe2x80x9cribs,xe2x80x9d slightly larger than the bore of the handle. When the handle is pushed onto the rubber ribs, the smooth bore compresses the rubber torch body ribs, and the resulting frictional engagement holds the handle in place. Such a securement of the handle is adequate for many applications and has several advantages. It allows the handle to remain cooler because the handle is not threaded onto a metal torch component that becomes heated during welding. It utilizes a simple push-on connection that is economical to manufacture and, when used with handles having variations in surface textures or contours, it allows the welder to rotate the handle on the torch body, giving the torch a different feel in the welder""s hand. By changing the orientation of the handle or the feel of the torch handle, the welder can reduce the strain and fatigue on his or her hand during a lengthy welding operation.
There are times, however, when it is important that the welding torch not rotate relative to the handle. For example, in a procedure known as xe2x80x9cwalking the cup,xe2x80x9d two pipes are welded together end-to-end. The operator first cuts the ends of both pipes at an angle and places the two ends together to form an outward-facing v-shaped groove. The operator then places the torch-mounted ceramic nozzle (called a xe2x80x9ccupxe2x80x9d) in the V-shaped groove of the pipe joint and moves the torch around the circumference of the groove by rocking the nozzle (xe2x80x9cwalkingxe2x80x9d) from side to side. The weld puddle coming from the welding torch penetrates the edges or walls of the weld joint, but preferably, does not enter the interior cavity of the pipe. With a normal rubber torch body and a friction-applied handle, the operator must apply a modest pressure to hold the nozzle on the pipe joint while xe2x80x9cwalking the cup.xe2x80x9d If the handle moves or rotates, the weld puddle can be affected, resulting in a faulty weld deposit. The faulty weld must be corrected, which is an expensive and time-consuming process.
The welding torch is typically hand-held by an operator. The operator often holds the handle of a welding torch for extended periods of time whether xe2x80x9cwalking the cupxe2x80x9d or performing other welding tasks. This can be quite tiresome and create joint strain on the operator""s hand, arm, and back. Further, the operator often must adjust the positioning of the torch or his or her own physical position in relation to the welding surface. This is particularly true when welding two pipes together. Thus, there is a need both for the adjustability of the handle provided by a friction-type connection and for a secure attachment which prevents inadvertent relative movement of the torch head and body.
It would be highly desirable to provide a welding torch that retained the favorable insulating properties and ease of adjustability of a rubber-insulated torch body and frictionally engaged handle but provided a securement that prevented unintended relative movement of the torch head and body. The welding torch of the present invention obtains these results. It would also be desirable for the welder to have a selection of handles with different surface contours, such that an operator could choose both the specific grip on a given handle for a particular torch or job or readily substitute one contoured handle for another, thereby enhancing the comfort and precision of the welding operation. The welding torch of the present invention allows for such selection and substitution.
Briefly, the welding torch of the present invention includes a frictional connection between an insulated torch body and the torch handle that prevents any inadvertent relative rotational movement therebetween. The torch body defines a first portion extending from the torch head and a second extended portion that carries the torch handle and frictionally engages the interior bore of the handle. An indexing member projects radially from the second portion of the handle that is adapted to be received within an axially extending groove formed in an inner end portion of a hollow handle upon the handle being pushed onto the torch body. When the handle is pushed onto the torch body, the handle is secured by frictional engagement and the indexing member on the body fits securely within the handle groove, preventing any inadvertent relative rotation of the torch body and handle during use.
In an alternate embodiment of the invention, the exterior surface of the torch handle is provided with at least two different contours that extend along the outer surface thereof and at least two axially extending grooves are provided in the inner end portion of the handle wherein each groove is radially aligned with one of the different surface contours. By selectively aligning one of the grooves on the torch handle with the indexing member on the torch body and urging the torch handle over the extended portion of the torch body such that the indexing member is received in that groove, the handle is secured on the torch body and the contour aligned with that groove is axially aligned with the torch body. By varying the groove into which the indexing member is inserted, the handle contour aligned with the torch body is varied. By varying the axial alignment of the contour of the handle with the torch body, the torch operator can reduce the strain and fatigue on his or her hand during use. In addition, multiple handles having different surface contours can be provided to give the operator a variety of comfortable gripping surfaces, based on the welding job requirements and preferences of the operator.
It is therefore the principal object of the present invention to provide an improved welding torch handle attachment.
It is another object of the present invention to provide a frictional engagement welding torch handle attachment that prevents inadvertent relative rotation of the torch handle and torch body during use.
It is a further object of the present invention to provide a welding torch having a torch handle secured on the torch body by frictional engagement that defines different surface contours and allows the operator to selectively vary the axial alignment of the contour of the torch handle with the torch body while preventing inadvertent relative rotation therebetween during use.
It is a still further object of the present invention to provide a welding torch assembly including a plurality of readily interchangeable welding torch handles having different surface contours that can be selectively secured on the torch body by frictional engagement such that inadvertent relative movement of the secured handle and torch body is prevented during use.
It is still another object of the present invention to provide a welding torch that minimizes strain and fatigue on the operator during use.
It is yet another object of the present invention to provide a highly versatile torch handle attachment which is of simple construction and economical to manufacture.
These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.